An integral step in many processes or systems for the production of textile fibers has been the collection of a rapidly moving filamentary strand in a container for transport to the next processing step. This process, often called piddling or canning, provides a means by which one or more filamentary strands (sometimes referred to as tow or rope) can be collected and possibly combined before processing through a draw/crimp step, which is often performed at a speed that has generally been much slower than the previous step, such as, for example, spinning a synthetic polymer to form synthetic filaments. A long-standing problem in the piddling process has been how to deposit such a rapidly-moving strand (e.g., a tow line) into the can in such a way as to avoid entanglements that may occur or be a problem upon subsequent removal of product from the can. Several methods are available commercially and/or have been published.
One system of piddling a textile rope has involved using a pair of toothed rolls to pull a tow from the primary (withdrawal) spinning rolls. Such toothed rolls, often referred to as gear rolls, gear plaiters or sunflower rolls, are available on piddler systems marketed by IWKA, Neumag, and Fleissner, for example. In these units, the toothed rolls are intended to pull the tow strand from a previous roll and to release the strand in such a way that it (1) does not wrap any rolls, and (2) is distributed so as to land softly in the can. To accomplish the first objective (a low wrap potential), large diameter rolls are used with many teeth to provide a small fiber contact area at the tip of each tooth. To enhance release of the filaments, the teeth are often coated with a low friction material and the surface speed of the toothed rolls is often greater than the speed of the moving tow band to enable the teeth to slip over the fibers and to avoid developing too much static friction. A soft landing of the moving tow line into the can is caused primarily by converting a large portion of the velocity of the moving tow band into a horizontal component. This is accomplished primarily by intermeshing the teeth from the two adjacent rolls so that the tow band folds upon itself. The vertical component of the velocity is further reduced by the tendency of filaments to adhere intermittently and momentarily to the teeth, which can cause the band to pull off its centerline and/or to open. We have noted several problems with this type of piddler. Their use is often limited in practical operations to low speeds of less than 1000 m/min owing to the difficulty of moving such (large diameter) sunflower rolls at high revolutions; we have experienced increased incidence of wraps at higher speeds. In addition, for a given product, we have found that the operating range of this type of equipment can often be relatively narrow, especially with certain types of filaments. In many instances, we have found that a mesh between the rolls that is too loose will result in poor can lay and resultant tangles, while a mesh that is too tight will result in the tow line wrapping the sunflower rolls. Wraps have also frequently been caused by wear and chipping of any low friction coating applied to the tooth surfaces. The higher speed of the sunflower roll teeth relative to the fibers can also result in broken filaments, which in turn can lead to dark dyed sections in subsequent fiber or fabric processing. Sometimes maintaining tension between the sunflower rolls and previous rolls has also been difficult. The nature of this type of piddler requires that only a light force be imparted on the filaments by the faster moving sunflower rolls since it is not desired to stretch the filaments at this point and since the higher speeds and/or tighter roll mesh required to give more tension can also result in sunflower roll wraps. To summarize, various problems have been experienced in practical operation of the toothed roll systems that are available commercially and improvements are desirable, especially when processing certain specific types of filaments on such toothed roll piddler systems.
Multifilamentary tows are not the only filamentary strands that have been laid down in the published art. Tillou in U.S. Pat. No. 3,270,977, Martin in U.S. Pat. No. 3,052,010, and Pflugrad in U.S. Pat. No. 3,135,038, disclose distributing strands referred to as tinsel conductors for telephone cords.
Disclosures of using a pneumatic jet for piddling textile strands date back almost 50 years, e.g., Koster in U.S. Pat. No. 2,447,982, Burns in U.S. Pat. No. 2,971,243, King et al in U.S. Pat. No. 3,706,407, and Goodner in U.S. Pat. No. 3,387,756. Burns required the force of the air to be sufficient to pull a tow (e.g., of synthetic polyester filaments) traveling at a speed of as much as 2500 ypm (2300 m/min) under a high tension while being below the tension required to draw the filaments. All of the above prior suggestions for using a pneumatic (or aspirating) jet piddler required rotating mechanical parts and angling of a discharge tube away from the tow line's vertical inlet position, which require complex apparatus, often in relation to rotating air joints and seals, and their maintenance.